Influenza Sentinel Site Surveillance Training Addis Ababa, Ethiopia: February, 2010

1. Influenza Sentinel Site Surveillance TrainingAddis Ababa, Ethiopia: February, 2010 Council of State and Territorial Epidemiologists United States Centers for Disease Control and Prevention

2. Part 1: Background and Objectives

3. Outline • Background • Purpose of the Training • Guiding Principles • Objectives of sentinel surveillance • Topics covered in the guidance

4. Global Burden of Respiratory Infections • Influenza: • 3 – 5 million cases of severe illness • 250,000 – 500,000 deaths • Lower Respiratory Infections: • Leading cause of death in low-income countries • 3rd leading cause worldwide

5. Need for Improved Surveillance • Historically, influenza surveillance data collection: • Virologic data for vaccine selection • Limited epidemiologic data • Lacked international standards • Remaining gaps in understanding: • Epidemiology, burden of disease • Social factors, clinical risk factors • Climatic factors

6. Global Surveillance for Influenza • WHO Global Influenza Surveillance Network (GISN) • International, laboratory-based (NICs) surveillance network • Provides virus strain information to select seasonal vaccine • National Influenza Centres (NICs) • Laboratories designated by national Ministries of Health and recognized by WHO to participate in GISN • 131 NICs, in 102 countries (as of Feb. 4, 2010)

7. Pandemic H1N1 (2009) • Timely virologic and epidemiologic monitoring at national level: • Track progression of pandemic • Track impact of pandemic • Convey an accurate perspective on severity and risk to population • Prioritize country-specific risk groups for intervention resources

8. Relatedness of Seasonal and Influenza Pandemic Preparedness Seasonal Influenza Preparedness Pandemic Monitoring

9. Surveillance Needs During a Pandemic • Is the situation changing? • Total amount of ILI, proportion of outpatient ILI due to influenza • Laboratory data to look at proportion of subtypes circulating in the community • Systematic sampling of viruses by age • How severe is the disease and is it changing? • SARI hospitalizations • Deaths (and ICU admissions) from sentinel hospitals • Clinical picture of hospitalized cases • Is the virus changing? • Drug resistance, drift and shift from laboratories • Comparison of viruses from less and more severe cases

10. Why is Monitoring the Severity/Virulence of a Pandemic Important? • Inform how aggressively we think about interventions, for example: • School closures • Stopping public gatherings • Vaccination priorities • Antivirals priorities • Mitigation, gain time to procure vaccine

11. Role of Sentinel Surveillance in Broader Monitoring Systems • Reporting of qualitative indicators • Aggregate reporting of laboratory-confirmed cases • Aggregate reporting of syndromes ILI/SARI/Mortality • Embedded sentinel sites to efficiently monitor • Virus characteristics • Severity and change in severity • Risk factors for severe illness • Hospital impact

12. Routine Value of Sentinel Surveillance • Routinely produce useful epidemiologic and virologic data • Identify priority groups for intervention (severe outcomes) • Accurately characterize circulating viruses • Monitor seasonality to prepare for influenza season • Compare provinces, countries and regions • Estimate burden of disease • Establish standards for surveillance reporting, collection and analysis • Provide a platform for the study of influenza and other respiratory pathogens

13. Guiding Principles: Short and Long Term Value • Integration into national systems • Standard case definitions for comparisons (ILI, SARI) • Efficiently monitor pandemic severity, high risk groups, and impact • Ongoing surveillance of influenza and other pathogens • High quality data in limited amounts

15. Topics Covered in Training Toolkit to establish a few high quality sentinel IP/OP sites • Criteria for selecting sentinel SARI and ILI sites • Methods to avoid bias in the selection of cases for testing • Epidemiologic data collection forms • Procedures for laboratory specimens • Report templates for weekly and annual data summaries • Techniques for routine monitoring of the surveillance system • Pandemic support functions

16. Part 2: Case Definitions

17. Deaths Hospitalized SARI Cases Medically-Attended Outpatient Cases Mild Disease, Not Medically-Attended Goal of Pathogen-based Surveillance: Global Burden of Influenza Pathogen-based surveillance SARI Surveillance ILI Surveillance Household Surveys/ Serum Surveys

18. SARI Surveillance • Should be priority/minimum basic influenza surveillance for countries with limited resources • Recommend adding this measure in countries with existing outpatient surveillance

19. SARI Case Definition > 5 Years Old • Any person requiring hospitalization* and presenting with manifestations of acute lower respiratory infection with: • sudden onset of fever (> 38 ºC) and • cough or sore throat and • shortness of breath, or difficulty breathing with or without clinical or radiographic findings of pneumonia, or • any person who died of an unexplained respiratory illness. * hospitalization may not be a required in some sites (i.e. remote from hospitals). Time requirement for onset of illness may vary.

20. SARI Case Definition < 5 Years Old IMCI case definition for pneumonia: • Any child aged 2 months to 5 years with cough or difficulty breathing and: • Breathing faster than 40 breaths / minute (ages 1 – 5 years) • Breathing faster than 50 breaths / minute (ages 2 – 12 months) *Note that infants less than 2 months of age with fast breathing of 60 breaths or more per minute should be referred for serious bacterial infection.

21. SARI Case Definition < 5 Years Old IMCI case definition for severe pneumonia: • Any child aged 2 months to 5 years with cough or difficulty breathing and any of the following: • Unable to drink or breastfeed, or • Vomits everything, or • Convulsions, or • Lethargic or unconscious, or • Chest indrawing or stridor in a calm child

22. ILI Case Definition • A person with: • sudden onset of fever >38°C, and • cough or sore throat in the absence of other diagnosis

24. Considerations When Using the SARI Case Definition • Fever requirement: may exclude elderly and immunocompromised • Option: do not include fever, or require a measured fever • May detect non-influenza viral pathogens • Will increase resource demands • Should record presence or absence of measured fever on the swab form for comparison to other countries • Ensure consistent application of case definitions across all sites

25. Experiences with SARI Surveillance Early data from Member States in 5 WHO regions suggests routine surveillance for SARI will…. …achieve virologic objectives of seasonal influenza surveillance (pct. positive similar to ILI during influenza season) …provide epidemiologic and virologic data on severe influenza infections …provide a basis for monitoring severe respiratory disease during a pandemic …serve as a platform for assessing burden of multiple viral respiratory pathogens

26. Prioritizing the Focus of the Surveillance System Simple Model • Budget: Low, no existing surveillance • Surveillance for: SARI as a minimum standard • Epidemiologic data collection (i.e., denominator data = total number of SARI or ILI seen) • Virologic testing • Small number of well-run sentinel sites preferred to large number of poorly-run sites.

27. Prioritizing the Focus of the Surveillance System Intermediate Model • Budget: Medium • Surveillance for: SARI and outpatient ILI • Virologic testing • Epidemiologic data collection (i.e. denominator data)

28. Prioritizing the Focus of the Surveillance System Advanced Model • Budget: High • Surveillance for: SARI and ILI surveillance • Virologic testing • Epidemiologic data collection (i.e. denominator data) • Multiple pathogens, possibly reduce fever requirement in inpatient setting as well

29. Part 3: Mechanics of Sentinel Surveillance

30. Outline • Sentinel site selection • Case sampling strategies • Epidemiologic data collection and forms

31. Selection of Sentinel Sites

32. What is sentinel surveillance? • One or more designated health care facilities that routinely collect epidemiologic information and laboratory specimens from patients presenting an illness consistent with a specified case definition • The system provides an efficient way to obtain high-quality data on relatively common conditions from a manageable number of locations

33. Why Sentinel Surveillance? • For monitoring/ identification of: • Identify target groups: • For antiviral use and timing • That might have greatest impact on transmission • Strains to include in vaccine • Appropriate management practices • Hospital staffing and procurement needs

34. Key Attributes of Sentinel Sites • Efficient data collection • High quality data • Limited number of well-chosen sites “A few high quality data are better than a lot of bad data”

35. The Efficiency of Sentinel Sites • Systematic testing of inpatient and outpatient (SARI and ILI) cases • Representation of viruses by age and severity • Efficient collection of demographic and epidemiologic data that is linked to virologic data • Can yield measures of disease burden • Valuable seasonally as well as in a pandemic • Can support efforts to monitor surge on hospitals

37. Ideal Characteristics of Sentinel Sites • Feasibility • People that are motivated to run the system • Political willingness for a site to participate • Sufficient staffing and laboratory capacity to maintain sampling and testing during healthcare surge • Efficient data management and transmission capability

38. Ideal Characteristics of Sentinel Sites • Patient representativeness • All ages • Wide range of medical conditions • For SARI surveillance, general or community hospitals are preferable to specialty care hospitals • For ILI surveillance, general outpatient clinics are often appropriate

39. Ideal Characteristics of Sentinel Sites • Quantifiable population denominator • Facilitates estimates of burden of disease • Requires understanding of population served by the sentinel site • Large referral hospitals may underestimate community incidence and require extra staff • Difficult to test a large proportion of all SARI cases identified • If calculating rates, may be difficult to assess the total population served by the surveillance site

40. Placement of Sentinel Sites • Population representativeness • Ethnicity • Socioeconomics • Climatic representativeness • Climate affects virus activity (transmission and viability in environment)

41. Example: Influenza Sentinel Site Selection in Cote d’Ivoire • Selection originally based on locations with confirmed AI and high poultry density/activity • Other considerations: • Health centers/hospitals that provide care to both adults and children   • Availability of staff • Availability of a cold chain • Status of the health center/hospital; public, private, religious • Availability of financial and material resources for setting-up & monitoring

42. Example: SARI sentinel sites in South Africa, 2009 Chris Hani Baragwanath Agincort Edendale Example: SARI Sentinel Surveillance in South Africa, 2009

43. Example: Sentinel Site Selection in Ukraine

44. Integration into National Clinical Reporting Systems • Ideally, sentinel sites could be integrated: • Adopt standard case definitions • Establish smaller number of sentinel sites within the broader universal reporting system • Assure high-quality data at these sites through more intensive training and oversight • Systematic laboratory testing only at sentinels • Broader clinical reporting provides valuable indicator of geographic spreadwithin a country

45. Integration into National Clinical Reporting Systems ILI/SARI Case-based epi data collection, laboratory testing ILI/SARI Syndrome Reporting ILI/SARI Syndrome Reporting ILI/SARI Syndrome Reporting ILI/SARI Syndrome Reporting ILI/SARI Syndrome Reporting ILI/SARI Case-based epi data collection, laboratory testing ILI/SARI Case-based epi data collection, laboratory testing ILI/SARI Syndrome Reporting

46. Selection of SARI Cases It is preferable to collect data and specimens from all or most SARI cases from a few facilities rather than a small sample of SARI cases from multiple facilities • Logistically feasible • Less bias • If not possible, an unbiased sampling protocol should be established

47. Selection of ILI Cases • Large number of cases at outpatient sentinel sites is likely • Total number of ILI cases seen is very important to collect • Collect specimens and case-based epidemiologic data from only a sample of ILI cases • Select cases for laboratory testing in as unbiased a manner as logistically possible

48. Sampling Methods for Respiratory Specimen and Case-based Epidemiologic Data Collection • Select all cases for testing • Select every xth case for testing • Select all cases on certain days of the week for testing • Select the first x cases on a certain day of the week

49. Selecting All Cases For Testing • Minimizes bias • Requires the most resources • May not be feasible in many settings • More feasible for sentinel surveillance focused on hospitalized cases (SARI)

50. Selecting Every Xth Case For Testing • Less likely to be biased than methods that only select cases on the same day or at the same time • Fewer resources than sampling all cases • Frequently used for hospital-based (SARI) surveillance